In time registering and programmable AC electric energy meters, also referred to as time of day meters, a programmable time based measuring system has a program sequence of operation. Measurement of one or more parameters of electric energy flow are measured in one of at least three time of consumption or usage categories. The sequence of operation is controlled by a meter program memory which accommodates certain replaceable and alterable meter control data so that the meter may be programmed for various measurement or billing rate schedules on a time and date basis. The meter control data also defines calculations and/or conversion factors and functions as well as time and date data which are required for calculations of selected energy parameters to be measured on a time basis. Typically, kilowatt demand and kilowatthour electric energy parameters are measured for the peak, intermediate or midpeak and base or low electric load demand times of an electric utility supplying distribution or system network. The meter measuring rate schedule has a timed schedule corresponding to the variations of power demand or loading of the electric energy supplier. The time of usage measurements are separately accumulated for billing at different rates.
It is desirable to electronically program the meters with the control data for various measuring schedules to produce measurements for the different billing rate times. Also, the programmed meter control data must be capable of being checked and authenticated. The electronically generated measuring data representing different parameters accumulated in different time categories are to be electronically read and stored in the field at meter installed locations. Since the measurements are made on a real time and date basis, checking and resynchronization of the time and date information is also required so that the energy flow measurements are in synchronism with the actual date and real time. Since meter initializing, programming and reprogramming, data checking, and meter data readouts may be done with large numbers of programmable meters at one time, or selectively in the field, data to be programmed and readout must be easily and conveniently accessed, recorded and checked with a minimum of time and operator steps.
Accordingly, it is desirable to have a portable self-contained programmer-reader (PR) unit which stores therein the replaceable and alterable meter control data of a programmable time registering electric energy meter in such a manner that the meter control data can be easily replaced or manually modified or corrected. Further, the PR unit must have its own time and date generating and accumulating operation for checking and resynchronizing the time and data registrations of the programmable meter. The PR unit also must be capable of recording the measurement data of the meter and visually displaying such data as well as performing certain checks and data verification steps and displaying and identifying any errors. Since the PR unit is used in the field, its operation must be maintained by batteries and a battery power conservation feature is to be incorporated for continuously powering only critical memory and timer circuits. The PR sequence controller is preferably periodically energized for time and date updating. Higher power consuming circuits are to be selectively energized whereby display, data entry, and data communication and transfer operations are powered during short time controlled periods so as to further conserve the battery power. Bulk data storage for field meter readouts of many meters is desirably transmittable to a central billing center requiring the meter data to be converted to a standard communications code such as may be receivable by a teletype writer printer.
The aforementioned requirements are provided by a portable PR unit described briefly hereinafter for a measuring system a programmable time registering AC electric energy meter.